Many communications systems benefit from secure communications provided by encrypted digital data packets. In prior art secure communications systems redundant encryption circuits have been employed to ensure that unencrypted data is not inadvertently transmitted. Encrypted data packets from the redundant encryption circuits are compared, and if they do not match, then an error has been detected, and transmission can be stopped.
This prior art scheme requires that redundant hardware or software be employed. When redundant hardware or software is employed for verification, errors are only found when the redundant functions do not behave identically. If a design flaw exists in either the redundant hardware or software, then identical errors will be produced in the redundant circuits and the error will go undetected.
Other prior art systems decrypt the encrypted data packets and compare the resulting decrypted data packets with the original unencrypted data packets. In secure communications systems, it is undesirable to maintain unencrypted data packets because this increases the possibility of a breach in security. This prior art scheme involving decrypting and comparing to the original data packet is undesirable because the original, unencrypted data packet must be maintained for purposes of comparison.
What is needed is a method and apparatus for encrypting data packets, and for verifying the proper encryption of data packets, without using redundant hardware or software. Also what is needed is a method and apparatus for encrypting and verifying the resulting encrypted data packets without maintaining an unencrypted version of the data packets.